The first announcement from Musk came on March 26, when he tweeted that the rock mined from the company’s California test tunnels would be turned into “Lifesize LEGO-like interlocking bricks made from tunneling rock that you can use to create sculptures & buildings.” The bricks would be sold as The Boring Company merchandise and are supposedly rated for California’s seismic loads.

New Boring Company merch coming soon. Lifesize LEGO-like interlocking bricks made from tunneling rock that you can use to create sculptures & buildings. Rated for California seismic loads, so super strong, but bored in the middle, like an aircraft wing spar, so not heavy.

Responding to critics on Twitter who were wondering why the tech entrepreneur wasn’t using his vast wealth to address the nationwide housing crisis, Musk followed up on May 7, indicating that those same bricks would now be sold on the cheap for low-cost housing.

A Boring Company representative confirmed the plans to Bloomberg, saying that the bricks used for housing would be made from the “excavated muck” of the company’s tunnels. These bricks would also go towards building any future Boring Company offices and could partially replace concrete in The Boring Company’s tunnels.

Of course, as Bloomberg points out, Musk’s plan to lower the cost of housing assumes that material costs are driving the price of construction, and not land or labor. Brick is expensive to lay because of the associated time and expertise it takes, not the bricks themselves (and this is before factoring in any type of structural reinforcement). It remains to be seen if The Boring Company can produce enough blocks to actually build any homes, especially as many of the prospective Hyperloop tunnels would be churning out dirt contaminated from years of industrial runoff.